Exhaust tube stop plug



1 59 s. G.CRESSWELL m1 2,911,015

EXHAUST TUBE STOP PLUG Filed Oct. 51, 1957 INVENTORS STEPHEN G. CRESSWELL KENNETH C. RUPERT 2,911,015 EXHAUST TUBE STOP PLUG Stephen G. Cresswell and Kenneth C. Rupert, Mill Hall, Pa., assignors, by mesne assignments, .to Sylvania Electric Products Inc., Wilmington, Del., :1 corpora: tion of Delaware Application October 31,;1957, Serial No. 693,574 7 6 Claims. f c1..141-6s This invention-.relates to tube exhausting machinery such as is utilized in electron tube manufacturing.

In a known machine of this type, one part of the machine seals a bulb, provided with a long exhaust tubulation, to aglass stem having the electrodes mounted thereon; Subsequently the so, sealed together tubu'lated bulb and stem is transferred, exhaust tubulation downward, into an exhaust port for exhausting the air from the bulb and for further processing thereofil This insertion of the tubulation into the port may be eficcted either manually or by mechanical automatic transfer mechanism on the machine. Preliminarily, the tubulation is adjusted in the port at a height above its metal ported bottom such that the top of the tube is at a fixed elevation for proper engagement of the tube leads with contacts on the machine during tube processing. This positioning is effected while port gaskets engage the tubulation and while they slidably frictionally retain the tubulation. After processing of the tube, sealing the same and separation of the tubulation from its bulb, the gaskets are released from tubulation engagement and the tubulation drops to the bottom of the port or is sucked down by residual suction in the port. Frequently chipping ofi of the bottom of the glass tubulation thereby ensues causing breakage of tubulated tubes later attempted to be inserted into the port and clogging of the exhaust passages leading from the port.

It is an object of this invention to provide a structure whereby this breakage of tubulation is minimized, as is also the clogging.

It is a further object of the invention to provide for ease in cleaning out the port in the event that clogging thereof does occur. 7

It is still a further object of the invention to provide a shock absorbing material at the bottom of the port to be engaged by the tubulation when released from the gaskets.

It is yet another object of the invention to provide for ease in replacement of the shock absorbing material when it becomes worn.

These and other objects will be understood upon consideration of the following specification when taken in conjunction with the accompanying drawing in which:

Fig. 1 is a plan view of a fragmentary portion of a machine embodying the invention.

Fig. 2 is a section through a portion of a suction port taken on the line 22 of Fig. 1.

Fig, 3 is a perspective view of a cup with a shock resistant material partially placed within the cup.

Fig. 4 is a vertical section taken through the cup.

Fig. 5 is a bottom plan view of the cup with vertical walls shown in dotted lines and Fig. 6 is a perspective view of the insert. 1

Now referring to the drawings in greater detail, at 10 there is indicated the table of an indexible turret, the same forming part of a combined tube sealing and exhausting machine. Mounted on the table there is a number of equally spaced circumferentially arranged sealing pegs 12 on which are placed the bulb assemblies 14 for sealing the bulb portion to the glass stem. These bulb assemblies. include a tubulation 16 which communicates with the interior of the bulb for the purpose of exhausting the same.

tubulations of the tubes are placed after removal from the sealing pegs. The tubes are placed in the assemblies so. that the-lead pins 22 are always at the same height for proper connection thereof with contacts on themachine 1 for tube lighting and bombardment of partstherein, as

is practised in the art. Any convenient means for adjust-.

ing the lead level may be utilized or the tubes maybe positioned at proper level manually, in accordance with the judgment of an operator.

.The. exhaust port'assembly may partake of various forms, all qualified however by incorporating the novel cup and shock absorbent insert to be described. In the application of the invention as here embodied, each post 20 comprises a nut 30 threaded into the table 10 with a suction duct 32 withinthe post flaring out into a wider at 44. The wall is slotted'through immediately above the passageway 34. The passageway is provided with a shoulder 36 forming a seat on which is placed the cup generically indicated as 38. The cup itself comprises a cylindrical wall 40 with a bottom 42 centrally perforated bottom as indicated at 46, leaving two opposite narrow vertical wall sections 48' joining the bottom to the cylindrical wall. The cylindrical wall is provided externally with a flange 50 at its upper edge and the inner surface of the cylinder down to the slot is threaded with a blunt edged thread 52 to receive a threaded cup puller, to provide for easy removal of the cup from the suction passageway for cleaning or replacement purposes.

Slipped'into the slot 46 is the insert 54. The insert is generally rectangular with rounded ends 56 and of a size to fit snugly in the slot 46 in the cup with the rounded edges flush with the outer cylindrical wall of the cup. The insert is centrally perforated at 58 to allow for passage of air therethrough and is made of fibre or yielding phenolic condensation product or other hard wearing, yielding shock absorbing material to prevent glass breakage on the tubulation dropping down or being sucked down into the insert, when the tubulation is released from its sealing means prior to its ejectment from the port, as by a blast of air through the suction port. Above the insert and mounted in a tubular extension 59 of the nut 30 is gasketry comprising a resilient ring 60 of neoprene, rubber, or the like, surmounted by a resilient cylinder 62 and another resilient ring 64, these being utilized to compress about the tubulation to form an air seal to hold the tubulation and tube in place for evacuation thereof and while the tube is otherwise Processed and also to ensure the cup being held against its seat. To compress the rings and cylinder there is mounted on the nut 30 a cylinder 66 with a coarse outer thread 68 threadedly receiving a nut 70 having an inturned flange 72 which, via a ball bearing 74, can bear down on a thimble 76 whose upper webbed wall has a centrally perforated conical depression 78 bearing on the upper resilient ring 64. Secured to the nut 70 is an actuating lever 79 operated in known fashion to compress the members, as by coaction with finger 80 in the path of movement of a projection 82 on the arm, as the turret indexes. Another member fixed on the machine is conventionally provided on the machine to rotate the lever in the opposite direction to release the tubulation. When this happens, the tubulation will come down against the fibre insert without glass breakage and therefore without creating debris which would afiect proper positioning of a subsequent tubulation in the port and without causing clogging of the passageways in the port.

Also mounted on the table .are circum ferentially equally spacedported posts 20 into which the 3 What is claimed is: 1. A post having, an upwardly extending passageway provided with a seat, a cup supported by said seat, said cup having a perforation in its bottom in fluid communication. with said passageway, and a shock absorbent i n sert supported within said cup, said insert having a, perforation in fluid communication with the perforation in atmosphere, said :post havinga suction passageway ex-,

tending upwardly therethrough, a seat formed in said passageway, a cup mounted on said seat, said cup having at perforation in its bottom,- a yielding insert mounted in the cup, said insert having a perforation therethrough, the perforations in the insert and cup being in fluid communication with the passageway, resilient gasketry above and pressing on said cup adapted to retain the cup on its: seat and to engage the tubulation to air seal the same, and means to compress the gasketry.

3. For use in a ported post on an electron tube evacuating machine, acylindrical cup having a bottom with a perforation therein, the cylindrical wall of the cup being slotted at opposite ends of a diameter of the cup with an insert of yielding material passing through the slotted wall and traversing the cup, said insert having a perfo ration registering with the perforation in the bottom of the cup.

4. For use in a ported post on an electron tube evacuating machine, a cylindrical cup having a bottom with a perforation therein, the cylindrical Wall of the cup being slotted at opposite ends of a diameter of the cup and an insert of yielding material passing through the slotted wall and traversing the cup, said insert having a perforation registering with the perforation in the bottom of the cup, the cup above the insert being internally threaded with a blunt edged thread to facilitate application of apulling tool totthe cup.

5'. For use in a ported post on an electron tube evacuating machine, a cylindrical cup having outwardly eX- tending flanged support means at its upper edge, a hoti tom having a perforation and a slotted cylindrical wall,

and a yielding insert within the cup passed through the slotted wall, said insert having a perforation registering with the perforation in the bottom of the cup.

6. For use in a ported post on an electron tube evacuating machine, a cupv having an. outwardly directed flange at the upper edge thereof and a bottom having the perforation therein, the side wall of the cup having opposite slots', a fibre insert passed through said slots and having a perforation registering with the perforation in the cup bottom, the outer edges of the insert conforming with the outer, wall of the cup. 7

References Cited in the file of this patent UNITED STATES PATENTS Edelmann July 7, 1936 2,788,028 Hartley et a1. Apr. 9, 1957 

